Abstract
In this paper the non-linear effect of massive neutrinos on cosmological structures is studied in a conceptually new way. We have solved the non-linear continuity and Euler equations for the neutrinos on a grid in real space in N-body simulations, and closed the Boltzmann hierarchy at the non-linear Euler equation using the stress and pressure perturbations from linear theory. By comparing with state-of-the art cosmological neutrino simulations, we are able to simulate the non-linear neutrino power spectrum very accurately for small to moderate neutrino masses. This translates into a negligible error in the matter power spectrum, and so our νCOnCEPT code is ideally suited for extracting the neutrino mass from future high precision non-linear observational probes such as EUCLID.